qml: make listmodel item count a property for channels and transactions

electrum/gui/qml/components/Channels.qml

@@ -123,12 +123,12 @@ Pane {
                     ScrollIndicator.vertical: ScrollIndicator { }
 
                     Label {
-                        visible: Daemon.currentWallet.channelModel.rowCount() == 0
+                        visible: Daemon.currentWallet.channelModel.count == 0
                         anchors.centerIn: parent
                         width: listview.width * 4/5
                         font.pixelSize: constants.fontSizeXXLarge
                         color: constants.mutedForeground
-                        text: qsTr('You have no Lightning channels yet in this wallet')
+                        text: qsTr('No Lightning channels yet in this wallet')
                         wrapMode: Text.Wrap
                         horizontalAlignment: Text.AlignHCenter
                     }

electrum/gui/qml/components/History.qml

@@ -83,7 +83,7 @@ Pane {
         ScrollIndicator.vertical: ScrollIndicator { }
 
         Label {
-            visible: Daemon.currentWallet.historyModel.rowCount() == 0
+            visible: Daemon.currentWallet.historyModel.count == 0
             anchors.centerIn: parent
             width: listview.width * 4/5
             font.pixelSize: constants.fontSizeXXLarge

electrum/gui/qml/qechannellistmodel.py

@@ -46,6 +46,12 @@ class QEChannelListModel(QAbstractListModel, QtEventListener):
     def rowCount(self, index):
         return len(self.channels)
 
+    # also expose rowCount as a property
+    countChanged = pyqtSignal()
+    @pyqtProperty(int, notify=countChanged)
+    def count(self):
+        return len(self.channels)
+
     def roleNames(self):
         return self._ROLE_MAP
 
@@ -113,6 +119,8 @@ class QEChannelListModel(QAbstractListModel, QtEventListener):
         self.channels = channels
         self.endInsertRows()
 
+        self.countChanged.emit()
+
     def on_channel_updated(self, channel):
         i = 0
         for c in self.channels:
@@ -141,6 +149,8 @@ class QEChannelListModel(QAbstractListModel, QtEventListener):
                 self.beginInsertRows(QModelIndex(), 0, 0)
                 self.channels.insert(0,item)
                 self.endInsertRows()
+                self.countChanged.emit()
+                return
 
     @pyqtSlot(str)
     def remove_channel(self, cid):
@@ -152,5 +162,6 @@ class QEChannelListModel(QAbstractListModel, QtEventListener):
                 self.beginRemoveRows(QModelIndex(), i, i)
                 self.channels.remove(channel)
                 self.endRemoveRows()
+                self.countChanged.emit()
                 return
             i = i + 1

electrum/gui/qml/qetransactionlistmodel.py

@@ -46,6 +46,12 @@ class QETransactionListModel(QAbstractListModel, QtEventListener):
     def rowCount(self, index):
         return len(self.tx_history)
 
+    # also expose rowCount as a property
+    countChanged = pyqtSignal()
+    @pyqtProperty(int, notify=countChanged)
+    def count(self):
+        return len(self.tx_history)
+
     def roleNames(self):
         return self._ROLE_MAP
 
@@ -147,6 +153,8 @@ class QETransactionListModel(QAbstractListModel, QtEventListener):
         self.tx_history.reverse()
         self.endInsertRows()
 
+        self.countChanged.emit()
+
     def on_tx_verified(self, txid, info):
         i = 0
         for tx in self.tx_history: